WordPress at a glance
function is not described

wp_send_new_user_notifications() WP 4.4.0

Initiates email notifications related to the creation of new users.

Notifications are sent both to the site admin and to the newly created user.

  • Since 4.6.0 Converted the $notify parameter to accept 'user' for sending notifications only to the user created.

No Hooks.

Return

Nothing (null).

Usage

wp_send_new_user_notifications( $user_id, $notify );
$user_id(int) (required)
ID of the newly created user.
$notify(string)
Type of notification that should happen. Accepts 'admin' or an empty string (admin only), 'user', or 'both' (admin and user).
Default: 'both'

Code of wp send new user notifications: wp-includes/user.php WP 5.2.1

<?php
function wp_send_new_user_notifications( $user_id, $notify = 'both' ) {
	wp_new_user_notification( $user_id, null, $notify );
}